Quantification of the Bruckner test for strabismus

Purpose. To measure quantitatively the change in the coaxial fundus reflex with varying degrees of ocular misalignment. Methods. The coaxial fundus reflex was imaged with a charge coupled device camera under conditions of stimulated ocular misalignment ranging from 0° to 7° of fixation eccentricity. The effects of refractive error and pupil size were controlled. Average gray scale brightness values were calculated for each bright pupil image after some image processing was performed on the raw images. Results. A reliable, sharply delineated, minimum brightness at foveal fixation was observed. Conclusions. It is estimated that this technique can he automated to detect the presence of 2° to 3° of ocular misalignment based on the difference in brightness of the bright pupil images between the two eyes.